<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app"></div>
<img src="https://www.runoob.com/wp-content/uploads/2016/02/ogimage.png" alt="" style="width: 60vw;height: 60vh;" >
<pre>

</pre>
    <script src="./src/react.js"></script>
    <script src="./src/react-dom.js"></script>
    <script src="./src/babel.js"></script>

    <script type="text/babel">
        class Title extends React.Component{
            constructor(){
                super();
                this.state={
                    n:1
                }
                console.log("属性")
            }
            // componentWillMount(){
            //     console.log("组件将要挂载到视图")
            // }
            componentDidMount(){
                console.log("组件已经挂载到视图--执行一次")
            }
            componentDidUpdate(){
                console.log("组件已更新 -- state props 更新后 就会执行")
            }
            jia=()=>{
                let n= this.state.n+1
                this.setState({
                    n:n
                })
            }
            
            componentWillUnmount(){
                console.log("组件将要销毁-- 执行一次")
            }

            render(){
                console.log("render渲染函数 -- state props 更新后 就会执行")
                return (
                    <div>
                        头部组件 {this.state.n}
                        <button onClick={this.jia}>点击+1</button>
                        
                    </div>
                )
            }
        }



        ReactDOM.render(
            <div>
                <Title ></Title>
                
            </div>,
            document.getElementById("app")
        )
        
    </script>

</body>
</html>